a. Field of the Invention
The instant disclosure relates generally to a family of medical devices. More particularly, the instant disclosure relates to medical devices, such as, for example, deflectable sheaths or catheter-introducers, having a generally planar element wrapped in spiral pattern about the sheath or catheter-introducer, where the generally planar element comprises a polymeric material. The instant disclosure further relates to deflectable sheaths or catheter-introducers having a generally planar element wrapped in a spiral pattern about the catheter-introducer or sheath wherein the generally planar element has a longitudinal axis and a plurality of longitudinally extending ribs. The instant disclosure further relates to methods of manufacturing such medical devices and systems with which such medical devices are used.
b. Background Art
Electrophysiology catheters are used in a variety of diagnostic and/or therapeutic medical procedures to diagnose and/or correct conditions such as atrial arrhythmias, including for example, ectopic atrial tachycardia, atrial fibrillation, and atrial flutter. Arrhythmias can create a variety of conditions including irregular heart rates, loss of synchronous atrioventricular contractions and stasis of blood flow in a chamber of a heart which can lead to a variety of symptomatic and asymptomatic ailments and even death.
A medical procedure in which an electrophysiology catheter is used includes a first diagnostic catheter deployed through a patient's vasculature to a patient's heart or a chamber or vein thereof. An electrophysiology catheter that carries one or more electrodes can be used for cardiac mapping or diagnosis, ablation and/or other therapy delivery modes, or both. Once at the intended site, treatment can include radio frequency (RF) ablation, cryoablation, laser ablation, chemical ablation, high-intensity focused ultrasound-based ablation, microwave ablation, etc. An electrophysiology catheter imparts ablative energy to cardiac tissue to create one or more lesions in the cardiac tissue and oftentimes a contiguous or linear and transmural lesion. This lesion disrupts undesirable cardiac activation pathways and thereby limits, corrals, or prevents stray errant conduction signals that can form the basis for arrhythmias.
It is well known to use a medical device called a sheath or catheter-introducer when performing various therapeutic and/or diagnostic medical procedures on or in the heart, for example. Once inserted into a patient's body, these particular medical devices (hereinafter referred to as “sheaths”) provide a path through a patient's vasculature to a desired anatomical structure or site for a second medical device, such as, for example, a catheter, a needle, a dilator, etc., and also allow for the proper positioning or placement of the second medical device relative to the desired anatomical structure.
To increase the ability to move and navigate a sheath within a patient's body, steerable sheaths have been designed. Steerable sheaths are often manipulated by selectively tensioning one or more pull wires running along the length of the sheath, typically offset from a central longitudinal axis of the sheath, thereby deflecting the distal end of the sheath in one or more planes. Pull wires (or other deflectable elements) can be disposed within lumens formed by tubes (i.e., so-called spaghetti tubes) that are manually bonded to an inner liner of the sheath. While commercially and functionally acceptable, the step of manually bonding the spaghetti tubes to an inner liner of the sheath increases the time and expense associated with manufacturing of the sheaths.
In addition, a sheath can include an optional braided wire assembly designed to reinforce the sheath and to transmit torque along the length of the sheath. The braided wire assembly can be formed of a metal such as stainless steel and can be formed in various braid patterns and densities. While commercially and functionally acceptable, a braided wire assembly can require manual processing of the braided assembly during assembly of the sheath (e.g., hand-stretching of the braided assembly).
Moreover, visualization of a sheath and/or its position has proved difficult. As a result, physicians have been unable to see the sheath and/or its position during the performance of a medical procedure without the use of ionizing radiation (e.g., acute x-ray delivery via a fluoroscope). However, with the advent and growing use of various automated guidance systems, such as, for example magnetic-based and robotic-based guidance systems, the need for such visualization capability has increased. More particularly, it is important for the physician/clinician operating such automated systems to know and understand exactly where the various medical devices being used are located and/or how they are positioned. In addition to the need for visualization in the use of automated guidance systems, the need for this capability also exists in certain instances where a physician manually controls medical devices. For example, the transseptal crossing point for procedures performed on the left side of a heart is not readily visible using fluoroscopy.